Tool and status for separating a femoral cup from an acetabular ball in an implanted hip prosthesis

ABSTRACT

Surgical tools which are used to separate from one another a femoral cup and an acetabular ball in an implanted hip replacement prosthesis. At its distal end, elements of the surgical tool engage the femoral cup and the acetabular cup. When proximal handles of the tool are squeezed toward one another, the engagement elements move away from one another. Thus, a surgeon is able to separate the femoral cup and the accetabular ball from one another without pulling the acetabular cup away from the acetabulum or the femoral cup and/or femoral implant away from the femur, thereby accomplishing the separation without disrupting any bone ingrowth.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to surgical instruments used in connectionwith a hip prosthesis. More specifically, the invention has to do withsurgical tools which are used to separate a femoral cup from anacetabular ball in an implanted hip replacement prosthesis.

The Related Art

A reverse hip prosthesis is described in U.S. Pat. Nos. 8,313,531 B2 and8,540,779 B2. The prosthesis and a revision surgery method also aredescribed in U.S. Pat. No. 8,992,627 B2. The disclosures of these threepatents are incorporated herein in their entireties by reference.

SUMMARY OF THE INVENTION

As described in the patents referenced above, a femoral cup articulateson an acetabular ball when the prosthesis is implanted in a patient. Theacetabular ball is affixed by means of a Morse taper to a stem which isaffixed to and extends from the bottom of the concave surface of anacetabular cup. The surgical tools of the invention enable a surgeon toseparate the femoral cup from the acetabular ball without pulling on theacetabular cup or the femoral implant and without disrupting any boneingrowth. The surgical tool of the invention may be included as acomponent of a kit containing other surgical instruments and/or implantelements.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top elevation view of a first embodiment of a surgical toolof the invention.

FIG. 1A is a top elevation view of the femoral engagement component 5 ofthe first embodiment.

FIG. 1B is an end elevation view of FIG. 1A.

FIG. 2 is a side elevation view of the first embodiment of the surgicaltool of the invention.

FIG. 2A is a bottom elevation view of an alternate embodiment of thesecond handle 3 of the first embodiment.

FIG. 2B is the same view as FIG. 2A following movement of the acetabularengagement component 6 a.

FIG. 3 is a side elevation view of the tool of FIG. 2 positioned on aprosthesis just prior to separation of the femoral cup from theacetabular ball.

FIG. 4 is a section view of FIG. 3 with a partial section of a femur asan added element.

FIG. 5 is a side elevation view of a second embodiment of the tool ofthe invention wherein the handles have been squeezed toward one another.

FIG. 5A is a perspective view of portion A of FIG. 5.

FIG. 6 is a perspective view of the second embodiment wherein thehandles have not been squeezed toward one another.

FIG. 7 is a top elevation view of FIG. 6.

FIG. 8 is a side elevation view of the second embodiment engaged with afemoral implant/cup and an acetabular cup before the femoral cup andacetabular cup are separated from one another.

FIG. 8A is a section view of FIG. 8.

FIG. 9 is a side elevation view of the second embodiment engaged with afemoral implant/cup and an acetabular cup after the femoral cup andacetabular cup have been separated from one another.

FIG. 9A is a section view of FIG. 9.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to the first embodiment, the surgical tool 1 of the invention,also referred to herein as a surgical instrument, is illustrated in atop elevation view in FIG. 1 and a side elevation view in FIG. 2. Thetool has a first handle 2 and a second handle 3. Springs 4 tend to biasthe handles apart from one another as illustrated in FIG. 2. The distalend of the first handle 2 has a femoral engagement component 5 attachedthereto and the distal end of the second handle 3 has an acetabularengagement component 6 attached thereto. Fulcrum pin 7 hinges the firsthandle 2 to the second handle 3 so that when the handles are squeezedtoward one another the femoral engagement component 5 and the acetabularengagement component 6 are moved away from one another. The pin 7 thusprovides a fulcrum between the first and second handles.

The femoral engagement component 5 illustrated in FIG. 1A is viewed fromthe direction of arrow A in FIG. 2. Femoral engagement component 5 maybe rotatably connected to first handle 2 by means of axis pin 5 a. Axispin 5 a allows a femoral engagement component 5 to rotate axially aboutthe central axis of the first handle 2. In FIG. 1B, an end view offemoral engagement component 5 is illustrated as taken from thedirection of arrow B in FIG. 1A. Arrow C in FIG. 1B illustrates thedirections in which femoral engagement component 5 can be rotated.

FIGS. 2A and 2B illustrate a bottom elevation view of an alternateembodiment of the second handle which is designated as 3 a. A hinge 3 bis provided on handle 3 a to allow lateral pivoting of a portion of thehandle located between pin 7 (see FIG. 2) and acetabular engagementcomponent 6 a. Hinge 3 b allows lateral movement in the directions ofarrow D of FIG. 2A. FIG. 2B provides an example of a hinged handle 3 ahaving an acetabular engagement component 6 a at the distal end thereof.

In FIGS. 3 and 4 the surgical tool 1 is positioned on a prosthesis justprior to separation of the femoral cup 20 from the acetabular ball 21.The acetabular engagement component 6 is engaged with thecircumferential edge 22 of acetabular cup 23 and the femoral engagementcomponent 5 is engaged with the neck 24 of femoral cup 20, or the outerhemispherical surface of femoral cup 20, or both the neck 24 and theouter hemispherical surface of femoral cup 20. And the femoralengagement component 5 may also engage the top (i.e., the proximal end)of femoral implant 25 which is implanted in femur 26, shown in partialsection. A liner 27 is illustrated in femoral cup 20. The acetabularball 21 is affixed to stem 28 of the acetabular cup.

When handles 2 and 3 or 2 and 3 a are squeezed toward one another, thefemoral cup is separated from the acetabular ball.

The second embodiment of the surgical tool of the invention is verysimilar to the first embodiment except for the acetabular engagementelement. This embodiment is illustrated in FIGS. 5-9A and it isdesignated as tool 31. A pivotable partial ring, referred to herein asacetabular engagement ring 36, is employed to engage the acetabular cupin the second embodiment as distinguished from acetabular engagementcomponent 6 in the first embodiment. The term “acetabular engagementelement” may be used herein to refer to both the acetabular engagementcomponent 6 and the acetabular engagement ring 36.

FIG. 5 is a side elevation view of tool 31. The tool has a first handle32 and a second handle 33. Springs 34, affixed to the handles withscrews 41, tend to bias the handles apart from one another. And in FIG.5, the handles have been squeezed toward one another to an intermediateposition between fully open as shown in FIG. 6 and fully closed as shownin FIG. 9. The distal end of first handle 32 has a femoral engagementcomponent 35 attached thereto. The distal end of second handle 33 has anacetabular engagement ring 36 pivotably attached thereto by means ofring pins 40. (See also FIG. 5A.) As can be seen from the drawings, ring36 is pivotable about an axis which is perpendicular to the central axisof the distal portion of handle 33. Fulcrum pin 37 hinges the firsthandle 32 to the second handle 33 so that when the handles are squeezedtoward one another the femoral engagement component 35 and theacetabular engagement ring 36 are moved away from one another. The pin37 thus provides a fulcrum between the first and second handles.

As in the first embodiment, the femoral engagement component 35 of thesecond embodiment may be rotatably connected to first handle 32 by meansof axis pin 35 a. Axis pin 35 a allows the femoral engagement component35 to rotate axially about the central axis of the first handle 32 inthe same manner as femoral engagement component 5 is allowed to rotateaxially about the central axis of first handle 2 in the firstembodiment. The alternate embodiment of second handle 3 a which has ahinge 3 b as described above (See FIG. 2B) can also be used with thesecond embodiment of the tool of the invention.

Referring to FIGS. 5A, 7, 8A and 9A, acetabular engagement ring 36 has abeveled edge 36 b which engages beveled edge 22 a of acetabular cup 23.Ring 36 also has a tab 36 a which is seated in indent 33 a to preventdownward rotation of ring 36 below the horizontal central plane of thedistal end of handle 33. Thus, as can be seen in FIGS. 6 and 7 whereinthe handles are in the fully open position, tab 36 a is seated in indent33 a and ring 36 is prevented from downward rotation in that position.

In FIGS. 8 and 8A the surgical tool 31 is positioned on a prosthesisjust prior to separation of the femoral cup 20 from the acetabular ball21. The beveled edge 36 b of acetabular engagement ring 36 is engagedwith the circumferential beveled edge 22 a of acetabular cup 23 and thefemoral engagement component 35 is engaged with the neck 24 of femoralcup 20 or the outer hemispherical surface of femoral cup 20, or both theneck 24 and the outer hemispherical surface of femoral cup 20. A femoralimplant 25 is also illustrated and the femoral engagement component 35may also engage the top (i.e., the proximal end) of implant 25. A liner27 is illustrated in femoral cup 20. The acetabular ball 21 is affixedto stem 28 of the acetabular cup.

When handles 32 and 33 are squeezed toward one another the femoral cupis separated from the acetabular ball as shown in FIGS. 9 and 9 a.

In the surgical method of the invention, femoral engagement component 5or 35 is engaged with the neck of the femoral cup, or an outerhemispherical surface of the femoral cup or both the neck and the outerhemispherical surface of the femoral cup and/or the upper surface (i.e.the proximal end) of a femoral implant. Simultaneously, the acetabularengagement component 6 is engaged with the circumferential edge 22 ofthe acetabular cup 23, or the circumferential beveled edge 36 b offemoral engagement ring 36 is engaged with the circumferential bevelededge 22 a of acetabular cup 23, and then the first and second handlesare squeezed toward one another thereby causing the femoral cup and theacetabular ball to be separated from one another.

1. A surgical tool adapted for separating a femoral cup from anacetabular ball in an implanted hip prosthesis comprising: a firsthandle and a second handle connected by a fulcrum pin in a hingedrelationship, the first and second handles being urged apart by aspring, each handle having a proximal end and a distal end; the firsthandle having a femoral engagement component at the distal end thereofand the second handle having an acetabular engagement element at thedistal end thereof; the fulcrum pin being disposed between the distaland proximal ends of each handle whereby movement of the proximal endstowards one another causes the distal ends to move away from oneanother; the femoral engagement component being sized to engage the neckof a femoral cup, or an outer hemispherical surface of the femoral cup,or both the neck and the outer hemispherical surface of the femoral cupand/or a proximal end of a femoral implant, and the acetabularengagement element being sized to engage a circumferential edge of anacetabular cup; the acetabular ball being affixed to a stem which isaffixed to the concave surface of the acetabular cup.
 2. The surgicaltool of claim 1 wherein the femoral engagement component is rotatablyconnected to the first handle.
 3. The surgical tool of claim 1 whereinthe femoral engagement component is connected by means of an axis pin tothe first handle, the first handle having a central axis and thefemoral! engagement component being axially rotatable about the centralaxis.
 4. The surgical tool of claim 1 further comprising a hingedisposed between the fulcrum pin and the acetabular engagement element,the hinge being arranged to allow lateral movement of the acetabularengagement element relative to the second handle.
 5. The surgical toolof claim 2 further comprising a hinge disposed between the pin and theacetabular engagement element, the hinge being arranged to allow lateralmovement of the acetabular engagement element relative to the secondhandle.
 6. The surgical tool of claim 1 wherein the acetabularengagement element is an acetabular engagement ring which is pivotablyattached to the distal end of the second handle.
 7. A kit containing thesurgical tool of claim
 1. 8. A kit containing the surgical tool of claim2.
 9. A kit containing the surgical tool of claim
 4. 10. A kitcontaining the surgical tool of claim
 5. 11. A kit containing thesurgical tool of claim
 6. 12. A method of using the surgical tool ofclaim 1 comprising engaging the femoral engagement component with theneck of the femoral cup, or an outer hemispherical surface of thefemoral cup or both the neck and the outer hemispherical surface of thefemoral cup and/or the proximal end of a femoral implant, whilesimultaneously engaging the acetabular engagement element with acircumferential edge of the acetabular cup and then squeezing the firstand second handles towards one another thereby causing the femoral cupand the acetabular bail to be separated from one another.
 13. A methodof using the surgical tool of claim 6 comprising engaging the femoral!engagement component with the neck of the femoral cup, or an outerhemispherical surface of the femoral cup or both the neck and the outerhemispherical surface of the femoral cup and/or the proximal end of afemoral implant, while simultaneously engaging the acetabular engagementring with a circumferential beveled edge of the acetabular cup and thensqueezing the first and second handles towards one another therebycausing the femoral cup and the acetabular ball to be separated from oneanother.